Electric connector plug



G. E. ANDRE ELECTRIC CONNECTOR PLUG June 18, 1940.

JunnnIlNM umreo STATES PATEVNT'OFFVICE ELuo'rmo CONNECTOR PLUG Gustaf E. Andre, Richmond, Ind., assignor to Belden Manufacturing Company, Chicago, 111., v

a corporation oi Hlllnois Application May 3, 1937, Qerial No. 140,421

4 Claims.

This invention relates to electric plug connectors and more particularly to the male type of plug connectors which are commonly used for connecting various electrical appliances and apparatus to a wall outlet or other similar source of electrical energy.

The main objects of-the invention are to provide a male connector plug which when inserted in an outlet. socket will establish good electrical connections between the terminals of the outlet socket and the conductor wires of the electrical cord whichcarries the plug; to provide a con nector plug of the type indicated which will fit and make good electrical contact with outlet sockets of both present day construction and older constructions which are now more or less abandoned, but many of which remain in older buildings; to providea plug connector of the type indicated which will have a tendency to more or less'lock itself in place in both new and old type outlet sockets; to provide a connector which will be simple and low in cost of construction, but which will be rugged, durable and efllcient in operation; and in generaL'it is the object of the invention to provide an improved electric connector plug of the type indicated.

Other objects and advantages of the invention will be understood by specification and acco reference to the following mpanying drawing, wherein there is illustrated a male type connector plug embodying a selected form of the invention and also the manner in which it cooperates with new and old type electric In the drawing:

outlet sockets.

Figs. 1. and 2 are, respectively front and side elevations of the selected form of the improved connector plug.

typical of present day the improved structure.

types of outlet sockets, and

Figs. 5 and 6 are front and side views, respectively, (partially in section) illustrating the cooperative relationship nector plug structure .bodying contact elements typical of old style between the improved conand an outlet socket emoutlet sockets. The plane of the section of the socket structure show indicated by, the line 55 on Fig. 6, and the plane of the section of the n in Fig. 5 is substantially socket structure shown in Fig. 6 is substantially as indicated by thelihe 6-6 on Fig. 5.

The improved conn ector plug structure shown wardly extending portions H, H.

such as indicated at 23 are pressed outwardly in Fig. 1 comprises a main body element in which may be of soft rubber in accordance with present day preferred practice, and contact prongs ii and I2,'respectively. The contact prongs extend into the body and have their inner end portions 5 l3, l3 suitably seated and anchored in the plug body so as to prevent withdrawal of the prongs. The body It! may be of one-piece molded construction, molded in place about the inner end portions l3, l3 of the contact prongs or the said body may comprise one or more parts molded or otherwise formed independently oithe contact prongs, and subsequently assembled with the contact prongs. Also, the body may be of hard or rigid material such as Bakelite, since the soft- 15 ness or inherent resiliency of the rubber plug body which is preferred is not required for the purposes of the plug construction herein contemplated.

duplex cord, has its conductor wires l5, it: re-

spectively connected within the body it to the inner end portions of the contact prongs. Any desirable means may be employed for anchoring the cord to the plug body so as to prevent excessive strain on the wire itself or connections of the wire with the contact prongs. Since such details are not material to the present invention they are not illustrated.

As indicated in Fi 1, the inner end portions l3, l3 fthe prongs are substantially straight. They may, however, be bent or shaped in any manner which will lend itself to the selected plug body construction.

The exposed or outer portions of the contact prongs H and I! are substantially alike, except that they are reverse in respect of the bends'or shaping. Each contact prong is bent inwardlyas indicated at l6 adjacent the front end of the plug body so as .to provide short, angularly, in-

The prongs are again bent as indicated at l8 so that the main lengths of the exposed prong portions extend slightly or gradually outwardly so that their free ends are spaced somewhat more than the por tions indicated at l9, l9 adjacent the bends l8.

At their free ends 20, 20, the springs are each I provided with an outwardly projecting hump 2| which, as clearly shown in Figs. 2 and 3, is in the form 'of a transversely extending outwardly projecting bead. The free ends of the prongs preferably, but not necessarily, have their corners beveled or chamfered as indicated at 22,.22, and short, longitudinally extending beads or ribs from the prongs. As shown, the longitudinally extending ribs 22 are disposed substantially centrally of the width of the respective prongs and the said ribs are so formed that their outer surfaces are substantially flush with the outer surfaces of the transverse beads 2| and gradually taper to and merge with the normal faces or surfaces of the respective contact prongs. v

The contact prongs H and I2 may be easily produced by simple stamping or punch press operations and they may be made from suitable material such as brass. They are preferably formed of spring brass of considerably less thickness than is conventionally used in forming the contact prongs of conventional connector plugs. Satisfactory results have been obtained by employing contact prongs made of material approximately one-thirty-second of an inch in thickness, the width of the prongs being approxiid in form, although not necessarily so. 7 In Fig. 4,

the socket terminals 24, 24 are shown as being those of a screw type plug which is provided for the purp se of converting an ordinary lamp socket or so-called Edison base socket into a female socket for receiving 'a male connector plug. 'It

wilL-however, be understood that the contact members 22, 24 illustrated in Fig. 4 are intended to typify the conventional practice in present day wall and like outlets. In the various forms of outlets typified by the outlet of Fig. 4, the contact prongs are usually separated by an intermediate portion 21 of' insulating material which is usually integral with the socket body, and the front end of the socket body .is equipped withopenings such as indicated at 28, 28, through which the connector plug contact prongs II and I2 may be inserted into the socket.

As indicated in Fig. 4, the portions IQ, "of the connector plug contact prongs are adaptedlto engage the opposite faces of the socket portion 21 so as "to be thereby urged outwardly to spread the free ends '22, 22 of the contact prongs. The spreading of the contact prongs, in a hard-bodied plug involves flexing of the prongs alone, but in the preferred form in which the body II is made of resilient material, the'body itself yields to a limited extent so that lessfiexing of the metal prong is required.

Spreading of the contact prongs II and i2 insures the making of good electrical contact-between the inner end rtions thereof and the free end portions of the rebent parts 22,22 or the socket terminals. The'arrangement is preferably such that the contact is effected between the protuberances 22, 22 and the outside faces of the respective prongs II and I2, and such that the free ends of the rebent terminal portions 25, 22 do not bear-on the contact prongs. Also, as indicated in Fig. 4. the arrangement is such that thelongitudinally extending rib portions 22, 22 of the contact prongs are in their entireties disposed in-' wsrdly of the said protuberances 22, 22, so that tuberances to efiect a gradual camming of the rebent terminal portions 25, 25 laterally outwardly incident to the endwise withdrawal of the prongs of the male connector plug. By this means there will be no scraping or gouging of the sur- 5 faces of the connector prongs by the relatively sharp edges of the free ends of the rebent terminal portions. Also, it will be observed that because of the spreading effect of the engagement of the prong portions l9, I2 with the socket body portion 21, the ribs 22, 22 have a definite tendency to resist withdrawal of the connector plug, in

other words, to more orless snap lock the plug in connected relation to the socket.

In Figs. 5 and 6, the outlet socket structure typifies the majority of old style outlet sockets which are found in existence in older buildings.

In such outlet sockets there are usually two sets of three terminal elements, each set comprising oppositely disposed terminal parts 29 and 22, and a third terminal element 2| which extends transversely of the terminal parts 22 and 22. As indicated in Fig. 6, the oppositely facing terminal elements 22 and 22 include substantially parallel portions 22 which have their free ends flared to 26 provide an entrance mouth. At the inner ends of the said parallel portions 22, 22 the said termi nals have oppositely diverging, angularly extending portions 22,22 which are integrally connected to a base portion. The bird member 2| of so each of said sets ofelemen .is also integrally connected with said base substantially as indicated in Fig. 5. The detailsof construction of the third element terminals varies somewhat in different manufacturers old style sockets, but 36 practically all of them included an arrangement which provided paralleh portions such as indicated at 22, 22, oppositely diverging portions 'such as indicated at 22, 22, arid a transversely extending portion 22. As indicated in Fig. 6, the trans- 0 versely extending bead portion 2| of each contact prong of the male connector plug fits against the inside faces of the diverging portions 22, 22, it

' being noted that the transversely extending bead 2| has its inner faces angularly disposed as clearly 5 indicated in Figs. 2, 3nd 6. The angular arrangement of the inner-faces of the transverse beads 2| is such that it substantially coincides with the average angular position of the portions 22.so that the said beads tend to lock behind said '50 angular terminal portions. The longitudinally extending rib' portion 22 of each prong more or less flts'in the normal spacing between the par- I allel portions 22 of the socket terminal elements.

The transversely extending terminal element 2| engages the inside of the straight intermediate portions of the prong members 1H and If, as shown in Fig. 5. and an intermediate portion ll of the socket body material engages the portions ll, ll of the contact prongs to effect spreading of the latter substantially as previously described.

It will be'observed that in the old style socket construction typified by Figs. 5 and 6, the spreading eflect produced on the contact prongs of the connector plug causes the establishment of good as electrical connection between the humped free ends of the contact prongs and the angular portions 22. 22 of the socket terminal elements. Such connection may in most instances be also enhanced by the backing provided by the trans- I struction embodies a relatively simple form of nary and simple punch-press operation. Hence the cost of producing the prong is very low. Also, because of the thinner weight of metal employed in making the improved contact prongs, the cost thereof is somewhat reduced over the cost of the heavier contact prongs employed in conventional constructions, even though a slightly more expen- -sive grade of metal be employed. The spring characteristic-oi the metal employed in contact prongs need not be very strong. It may be relatively light since the structure of the socket itself tends both to spread the contact prongs and to resist their spreading. The spreading effect is of course that produced by engagement of the prong portions I9, I! and the resistance to spreading occurs where the contact prongs 'engage the terminal elements of the socket.

Changes in the described construction may be made without departing from the spirit of the invention, the scope of which should be determined by reference to the following claims, the same being construed as broadly as possible consistent with the state of the art.

I claim:

1. An electric connector plug comprising a body of insulating material and a pair of contact prongs carried by said body and projecting from the front end thereof, said prongs each having rear portions adjacent the body arranged in forwardly converging relationship to each other and, beyond said converging portions, front portions of substantially straight form disposed in forwardly diverging relationship,- the free ends of each prong being provided with a transversely extending detent rib and a second detent rib extending at an angle to the first-named rib and positioned inwardly from said first-named rib, said ribs adapted to cooperate respectively with corresponding detent portions of two different types of electrical outlets.

2. An electric connector plug comprising a body of insulating material and a pair of contact prongs carried by said body and projecting from thefront end thereof, said prongs each having rear portions adjacent the body arranged in forwardly converging relationship to each other and, beyond said converging portions, front portions of substantially straight form disposed in forwardly diverging relationship, each of the front portions of said prongsbeing provided adjacent their forward ends with a lateral offset adapted to cooperate with a portion ofa predctermlnedtype of electrical outlet for resisting withdrawalof the connector plug'thereirom. and each of said front portions being provided with v a second ,offset spaced'longitudinally from said ilrst mentioned offset and adapted to cooperate with a portion of another type of electrical outlet for resisting withdrawal of the connector plug from such other type of outlet. 7 I

3. An electric connector plug comprising a body of insulating material and a pair of contact prongs carried by said body and projecting ffrom the front end thereof, said prongs each having rear portions adjacent the body arranged in forwardly converging relationship to each other, and, beyond said converging portions, front portions of substantially diverging relationship,

the front portions of said prongs adjacent their forward ends being provided with inwardly facing transverse oflsets and longitudinal beads, the latter beingdisposed centrally of the width of the prongs, intersecting said offsets and extending a; short distance rearwardly of the prongs,

thereby to provide longitudinally spaced shoulden portions respectively adaptedto cooperate with portions of different types of electrical outlets for resisting separation of the connector plug from such outlets. l

4; A connector plug according to claim 3 wherein the transverse offset on each prong comprises rearwardly facing side portions arranged to form an obtuse. rearwardly facing angle,

whereby said angularly disposed side portions 7 are adapted to flt portions of the terminals of a conventional type of electric outlet.

GUSTAF E. ANDRE. 

